I thought I would pass on a interesting finding while doing some modifications to my 21BHS. I found that the gray aluminum skin panels on bunk beds top and bottom sheets still had the plastic protective covering over the painted surface. It's fine to leave it on if you want to protect the paint when using bunk for storage, instead of bed with mattress. If you notice the surface looking funny, bubbles, or scrapes it might be the plastic film. You can use your fingernail or a soft plastic scraper in the corner to scrape the plastic up off the panel and then pull it off completely. You will see a shiny painted surface compared to dull looking gray painted panel. I found the same plastic on the metal sheeting under the upper cabinet over the sink and stove. The aluminum gray panel material is the only pieces that I have seen covered in plastic as part of manufacturing process. I think it looks nicer with plastic removed, shinny finish.
Peter